As glass substrates are used in a greater number of applications, the ability to control various attributes of the glass has become increasingly important. In particular, maintaining specified thickness attributes of the glass sheet is important for many consumer device applications, since variations outside of the specifications can impact the fit of the glass substrate and/or the final overall size of the device.
Conventionally, downdraw processes are used to manufacture a glass ribbon that can be singulated into discrete glass sheets. Flow and temperature variations in the molten glass from which the glass ribbon is formed can result in glass defects, such as variations in the sheet thickness and other effects. As such, controlling the flow and temperature of the glass can be used to minimize variations in the thickness of the glass ribbon. However, conventional methods that compensate for long term variations in the thickness of the glass ribbon can amplify short term variations in the thickness of the glass ribbon, resulting in increased manufacturing losses and production costs.
Accordingly, alternative methods for controlling the thickness in a glass ribbon are needed that address both long term and short term variations in the thickness to reduce thickness variations in glass sheets formed from the glass ribbon.